<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
    var arr = [3,4,5,6];
    for (var i = 0; i < arr.length - 1; i++) {
        for (var j = 0; j< arr.length - 1-i; j++) {
            if (arr[j] > arr[j + 1]) {
                temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
    console.log(arr);
</script>
</body>
</html>